Development of UV Distribution Model for the Non-Contact Type UV Disinfection System

Abstract

Fouling on the quartz sleeve reduces the transmittance of UV light through the sleeve into the water in submerged UV disinfection system. The concept of a non-contact type of UV disinfection system was introduced in this study. UV lamps and their quartz sleeves hang over the water surface and there is no interface between the sleeve and water. Indeed, there is no fouling. Based on optical laws and UV distribution model, a detailed mathematical model for a non-contact type UV disinfection system was developed and simulated in this study. UV light passes through 4 media of air-quartz-air and water in case of non-contact type irradiation system. By the simulation of the mathematical model of the system, it is known that the non-contact type of UV system requires 2.5 times more powerful UV lamp or a lamp with longer exposure time than that of the submerged type of UV system. In a non-contact type of UV system, high-reflective ceiling material can increase the UV intensity of the water layer as much as 28 percent more than the case of non-reflective ceiling material. The non-contact type UV irradiation system requires more powerful lamp or one that have longer exposure time. Nevertheless, considering the fouling attenuation and maintenance problem associated with the fouling, non-contact type of UV disinfection system deserves to be practically considered, especially in a small to middle scale water or wastewater treatment plant.